TABLE 1

Fourteen Patient Characteristics (Variables) Considered as Potential Predictors of Hematologic Toxicity (32 Patients)

VariableMean ± SDRangen
Age at radioimmunotherapy (y)63 ± 1040–80
Number of prior chemotherapy regimens at radioimmunotherapy (including rituximab)3.1 ± 1.71–8
Time since last chemotherapy (mo)8.9 ± 6.41–26
Bone marrow dose (Gy)1.6 ± 0.4*1.0–2.0*
2.1 ± 0.4†1.2–2.8†
Baseline at time of radioimmunotherapy
    Platelets (103/mm3)206 ± 10067–535
    Absolute neutrophil count (1/mm3)3,860 ± 1,8801,530–11,080
Male sex23 (72%)
Type of radioimmunotherapy agent
    90Y-ibritumomab tiuxetan14 (44%)
    131I-tositumomab18 (56%)
Disease stage at radioimmunotherapy
    I–II5 (16%)
    III–IV27 (84%)
Prior treatment with rituximab
    Alone8 (25%)
    With chemotherapy23 (72%)
Refractory to rituximab14 (44%)
Bone marrow involvement at radioimmunotherapy7 (22%)
History of prior bone marrow transplant4 (13%)
History of prior radiation therapy7 (22%)
History of prior treatment with fludarabine9 (28%)

  • ↵* For patients treated with 90Y-ibritumomab tiuxetan, BMDs were obtained from BMD per unit activity reported in package insert provided by the manufacturer (11).

  • ↵† For patients treated with 90Y-ibritumomab tiuxetan, BMDs were obtained from BMD per unit activity reported by Fisher et al. (12).